The present invention relates to an interior structure of a vehicle equipped with a curtain airbag, and, in particular, relates to an interior structure of a vehicle equipped with a curtain airbag which is disposed inside a roof trim in a stored state.
Conventionally, a curtain airbag device equipped with an airbag which inflates downward from the ceiling portion into the vehicle compartment in a curtain shape (hereinafter, referred to as a “curtain member”) at a vehicle side collision or rollover is known. This curtain airbag device is configured to reduce the collision impact at the vehicle side collision or to cover a side window for protection of passengers at the vehicle rollover.
Japanese Patent Laid-Open Publication No. 2007-15536, for example, discloses the curtain airbag device in which the curtain member in the stored state is provided inside the roof trim at a roof side rail portion. According to this curtain airbag device, the volume of part of the end portion of the curtain member which is stored inside the pillar trim is set to be so less than the volume of that which is pulled back at the time of inflation that the inflation function of the curtain member can be properly ensured, reducing the degree of projection of the roof trim into the vehicle compartment when the curtain member is stored.
Herein, it may be considered that the curtain member is stored in such a manner that a side end portion (an end portion in a vehicle longitudinal direction) of the curtain member is turned back (bent), i.e., the curtain member has a bending portion. Thereby, when the curtain member inflates, the roof trim may be deformed and the pillar portion which is located forward or rearward may be covered properly with this side end portion (bending portion) of the curtain member which inflates into the vehicle compartment. Thus, the large inflation range of the curtain member can be ensured, thereby improving the safety against the vehicle collision, keeping an outlet opening of the curtain member at an interior member as smaller as possible.
Herein, however, fixing of the curtain member to the vehicle body is only conducted at the upper portion of the roof side rail portion, not at a pillar portion which is provided in fort or back of that, so a so-called “tension line” which should be formed so as to extend in the vehicle longitudinal direction by connecting a fixing point of the front end of the vehicle body (a front pillar) and a fixing point of the rear end of the vehicle body (a rear pillar) may not be formed properly. If this tension line is not formed at the curtain member, there is a concern that the curtain member may not keep its inflating state properly covering the side window.
Further, EP 1386791 A2 discloses the airbag device in which the curtain member in the stored state is disposed at the upper edge portion of the back window at the vehicle rear portion. This curtain member inflates downward so as to cover the back window from the inside of the vehicle compartment when the rear impact is detected. Further, this publication also discloses the airbag device to guide the inflation direction of the curtain member with a pair of guide rails which are provided at both-side edge portions of an opening of the back (rear) window. Thus, the curtain member can be guided properly and cover the back (rear) window surely.
Herein, since the curtain member has a tension in the vehicle width direction by providing the guide rails, the above-described tension line can be formed in the vehicle width direction at the curtain member. However, there is a concern that according to the structure of the airbag device in the above-described European publication the curtain member may not inflate stably because the curtain member could not smoothly slide on the guide rails if the inflation speeds at the both sides of the curtain member are different from each other.
Accordingly, it may be considered as another structure for providing the tension line to the curtain member without any guide rail that the curtain member is directly fixed to the both-side edge portions of the opening of the back window so that the curtain member inflates from the both-side edge portions. Herein, it may be necessary that inner-wall faces (pillar trims) of the both-side edge portions should be deformed greatly or broken in this structure. However, this may be difficult because the pillar trim provided at the both-side edge portions of the opening is generally made of a hard material of synthetic resin so as to form a luggage-space wall face. Thus, there is a concern that the tension line may not be properly formed at the curtain member according to the present structure, either.
Meanwhile, in the curtain airbag device disclosed in the above-described Japanese patent publication, the curtain member is stored in such a manner that the side end portion of the curtain member is turned back, i.e., the curtain member has the bending portion, as described above. Accordingly, there is a concern that the inflation of the side end portion of the curtain member (i.e., the bending portion) toward the vehicle compartment may be improperly delayed, so that the safety against the vehicle collision would deteriorate.